error-test.c false positive when building tarballs in maintainer mode

[Daniel Shahaf]

Investigating this failure:

    
/tmp/svn-dist/subversion-1.13.0//./subversion/tests/libsvn_subr/error-test.c:224:
 (apr_err=SVN_ERR_TEST_FAILED)
    svn_tests: E200006: Strings not equal
      Expected: 'ENOENT'
      Found:    '(null)'
      at 
/tmp/svn-dist/subversion-1.13.0//./subversion/tests/libsvn_subr/error-test.c:224
    FAIL:  error-test 3: test svn_error_symbolic_name

The test code is in subversion/tests/libsvn_subr/error-test.c:

   185  static svn_error_t *
   186  test_error_symbolic_name(apr_pool_t *pool)
   187  {
   188    struct {
   189      svn_errno_t errcode;
   190      const char *errname;
   191    } errors[] = {
   ⋮
   208  #ifdef SVN_DEBUG
   209      { ENOENT, "ENOENT" },
   210      { APR_ENOPOOL, "APR_ENOPOOL" },
   211  #endif
   ⋮
   219    };
   ⋮
   222    for (i = 0; i < sizeof(errors) / sizeof(errors[0]); i++)
   223      SVN_TEST_STRING_ASSERT(svn_error_symbolic_name(errors[i].errcode),
   224                             errors[i].errname);

svn_error_symbolic_name()'s support for OS error codes, such as ENOENT, is
implemented in build/generator/gen_base.py:

   264    def write_errno_table(self):
   265      # ### We generate errorcode.inc at autogen.sh time (here!).
   266      # ###
   267      # ### Currently it's only used by maintainer-mode builds.  If this
   268      # ### functionality ever moves to release builds, it will have to 
move
   269      # ### to configure-time (but remember that Python cannot be assumed 
to
   270      # ### be available from 'configure').
   271      import errno
   ⋮
   299      # errno names can vary depending on the Python, and possibly the
   300      # OS, version and they are not even used by normal release builds
   301      # so omit them from the tarball. We always want the struct itself
   302      # so that SVN_DEBUG builds still compile and it needs a dummy
   303      # entry to avoid a zero-sized array.
   304      write_struct('svn__errno',
   305                   [(0, "success")] if self.release_mode
   306                                    else errno.errorcode.items())

«self.release_mode» is true when gen-make.py is run by «autogen.sh --release»,
which is how autogen.sh is run by the tarball rolling scripts.

Consequently, the ENOENT test case fails when building a tarball with
--enable-maintainer-mode.

I'm not sure how to fix it.

Could we just guard the ENOENT test case with «#if SVN_VER_REVISION == 0»?
That would be mostly correct, though the guard wouldn't be necessary when
building tags from a working copy (rather than tarball) in maintainer mode.

Cheers,

Daniel